The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
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Taking Mounjaro Every 5 Days in the UK
Mounjaro (tirzepatide) is designed as a once-weekly injection, and it's important to understand why the standard dosing schedule matters for your safety and effectiveness. This guide explains whether you can take Mounjaro every 5 days, how the prescribed schedule works, and what you need to know about accessing this prescription-only medicine in the UK through both NHS and private routes.
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Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
Why Mounjaro Is Prescribed Weekly — Not Every 5 Days
Mounjaro is specifically formulated as a once-weekly injection, and this timing is not flexible. Clinical trials and safety monitoring have established that doses should be taken at least 72 hours (3 days) apart — meaning you cannot safely take Mounjaro every 5 days as an established routine.
The medication works by building up in your system over time. Each dose of the tirzepatide KwikPen is calibrated to release a consistent amount over seven days. If you take doses more frequently than recommended — such as every 5 days — you risk:
- Overdosing and increasing side effects like nausea, vomiting, and stomach pain
- Disrupting the steady-state hormone regulation the medication relies on
- Creating unpredictable appetite suppression and metabolic effects
- Potentially damaging your pancreas or gallbladder due to concentrated doses
If you've missed a dose and it's been less than 4 days, you can take it as soon as you remember and continue your normal weekly schedule. Your prescriber will always provide clear guidance on your personal dosing schedule.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
Accessing Mounjaro in the UK — NHS and Private Routes
In the UK, accessing Mounjaro depends on your route: NHS specialist services or private prescription. For NHS access, you'll need referral to a tier 3 specialist weight management service from your GP. Waiting lists vary significantly by region, and availability depends on your local Integrated Care Board (ICB) funding. The NHS may cover Mounjaro if you meet eligibility criteria: BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or high blood pressure.
For private access, you can obtain a prescription following an online consultation with a UK-licensed prescriber. This typically costs £130–£300 per month depending on your dose — cost varies as you titrate from 2.5 mg up to your maintenance dose. Most private prescriptions are dispensed by GPhC-registered pharmacies and delivered to your home. You'll need to arrange repeat prescriptions monthly.
Online consultations for private Mounjaro typically involve completing a health questionnaire, discussing your medical history, and being assessed for suitability. A qualified prescriber will review your BMI, any existing health conditions, current medications, and contraindications — including pregnancy or breastfeeding status. If approved, your prescription is issued and sent to a UK pharmacy for dispensing. This process usually takes 24–48 hours from consultation to first delivery. You'll also receive guidance on injection technique, storage (refrigerated until use, then room temperature for up to 30 days), and how to report side effects. Using our GLP-1 weight loss calculator above can help you understand potential results at different doses while you're exploring access options.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
Can I take Mounjaro every 5 days instead of weekly?
No. Mounjaro must be taken as a once-weekly injection, with a minimum of 72 hours (3 days) between doses. Taking it every 5 days as a routine would be unsafe and is not recommended. Always follow your prescriber's schedule. If you've missed a dose, contact your prescriber or pharmacist for guidance.
What's the difference between Mounjaro and Wegovy dosing schedules?
Both are once-weekly injections with similar minimum spacing (72 hours between doses). Mounjaro (tirzepatide) is a dual GIP/GLP-1 agonist reaching 15 mg maximum dose, while Wegovy (semaglutide) is a GLP-1 agonist only, reaching 2.4 mg maximum. Dose titration schedules differ, but both require weekly consistency.
How much does Mounjaro cost privately in the UK?
Private Mounjaro typically costs £130–£300 per month depending on your dose. Starting doses (2.5 mg) are usually at the lower end; maximum doses (15 mg) are higher. Prices vary between pharmacies. Most include delivery. NHS access depends on your region and specialist service availability — there's typically no out-of-pocket cost once prescribed through NHS.
What happens if I miss a Mounjaro dose?
If fewer than 4 days have passed, take your dose as soon as you remember and continue your normal weekly schedule. If more than 4 days have passed, skip that dose and take your next injection on your normally scheduled day. Never double-dose. Always inform your prescriber if you've missed multiple doses.
How do I access Mounjaro through the NHS in the UK?
Ask your GP for a referral to your local tier 3 specialist weight management service. You'll be assessed for eligibility (BMI ≥30, or ≥27 with weight-related conditions). If approved, the NHS specialist service will prescribe and monitor your treatment. Waiting times and availability vary significantly by region and ICB funding.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.